Coupled Waveform Analysis in Dynamic Characterization of Lossy Solids

Abstract

By means of the viscoelastic wave propagation model for a homogeneous semi-infinite solid, a rational analytical and computational framework is developed for nonintrusive, wave-based characterization of lossy media. The problem of estimating the equivalent uniform material properties from surface observations is formulated in the Bayesian setting for two canonical testing configurations, one involving a vertically and the other a horizontally polarized wave field. By enhancing the treatment of the inverse problem through a fully coupled viscoelastic analysis of the observed waveforms, the method provides consistent estimates of the in situ material stiffness, damping, and density which are not available from conventional seismic interpretations. For a rigorous treatment of the gradient search technique employed by the inverse solution, the necessary derivatives of the predictive model are evaluated analytically. A set of results with noise-contaminated synthetic measurements is included to highlight several key features of the back analysis.